ECOLOGICAL SOUNDING
© 2003 Blackwell Publishing Ltd. http://www.blackwellpublishing.com/journals/geb
Global Ecology & Biogeography (2003) 12, 1–3
Blackwell Publishing, Ltd
Island ecology and contingent theory: the role of
spatial scale and taxonomic bias
ANDRÁS BÁLDI*‡ and DUNCAN MCCOLLIN†
*Animal Ecology Research Group of the Hungarian Academy of Sciences, Hungarian Natural History Museum, Ludovika tér 2, Budapest, Hun-
gary, H-1083, E-mail: baldi@ludovika.nhmus.hu, †Landscape and Biodiversity Research Group, School of Environmental Science, University
College Northampton, Park Campus, Northampton NN2 7AL, U.K., E-mail: duncan.mccollin@northampton.ac.uk
ABSTRACT
Scale, the scale dependency of patterns and processes,
and the ways that organisms scale their responses to these
patterns and processes are central to island and landscape
ecology. Here, we take a database of studies in island ecology
and investigate how studies have changed over a 40-year
period with respect to spatial scale and organisms studied.
We demonstrate that there have been changes in the spatial
scale of islands studied and that there is taxonomic bias in
favour of vertebrates in island ecological studies when
compared to scientific publications as a whole. We discuss
how such taxonomic bias may have arisen and discuss the
implications for ecology and biogeography.
Key words invertebrates, island area, island biogeography,
island ecology, plants, spatial scale, vertebrates.
Ecological patterns and the laws, rules and mechanisms
that underpin them are contingent on the organisms
involved and their environment (Lawton, 1999, p. 177).
There is an increasing recognition of the importance of
scale and the scale dependency of patterns and processes in
ecology, and the ways that organisms scale their responses to
these patterns and processes (Levin, 1992; Wiens et al ., 1993;
Hubbell, 2001). Here, we investigate how studies in island
ecology have changed over a 40-year period with respect to
spatial scale and the organisms studied. Island ecology has a
long pedigree in ecology and biogeography, stretching at
least as far back as the work of Alfred Russel Wallace (1880),
although in recent years island ecology has been dominated
by island biogeography sensu MacArthur & Wilson (1967)
(Whittaker, 1998). The MacArthur–Wilson model is based
on the assumption that the numbers of species found on islands
is a balance between the opposing rates of immigration and
extinction, the latter influenced by island area acting on
population size and the former influenced by distance from
the mainland. As such, a common methodological approach
has been to count numbers of species on a sample of islands
(oceanic or habitat) of differing sizes and relate patterns of
species richness to geographical (e.g. area, isolation) or
physical (e.g. habitat diversity, altitude) attributes of islands
(e.g. McCollin, 1993; Báldi & Kisbenedek, 2000). Alternative
approaches, using more intensive studies on a smaller range
of islands (e.g. Blondel et al ., 1999), can also be very inform-
ative but tend to be much less common.
We ask whether there are trends in the spatial scales chosen
by researchers working in island ecology over time and
whether there are trends in taxa studied. If any such trends
exist we ask what are their causes and query whether they
are exclusive to island ecology or whether they reflect a more
fundamental bias or lack of rigour in ecological method.
These are important questions not just for island ecology, but
potentially have wider implications for landscape ecology and
biogeography.
We use a pre-existing dataset assembled by Wright et al.
(1998) for their analysis of nestedness in ecological commun-
ities. The spread of papers in this dataset is not comprehen-
sive, but it does represent a large sample of studies published
between 1933 and 1993. The 163 independent data matrices
used by Wright et al. (1998) include useful information for
such an analysis including taxon, location and island size,
among others (see www.aics-research.com/nested). In
order to test this dataset for trends with respect to spatial
scale, data for numbers of species, numbers of islands,
minimum and maximum area were entered into correlation ‡ Corresponding author.